Liquid crystal display device

ABSTRACT

A liquid crystal display device includes a plurality of pixels, a plurality of image signal lines for applying a plurality of gray scale voltages to the plurality of pixels, and an image signal line drive unit including a film substrate and a semiconductor integrated circuit device formed on the film substrate. The semiconductor integrated circuit includes a plurality of input terminals, a plurality of output terminals, a first terminal, and a second terminal. The film substrate comprises a plurality of first wirings, a plurality of second wirings, and a third wiring. The third wiring and the first terminal are connected between the semiconductor integrated circuit device and the film substrate, and the third wiring and the second terminal are connected between the semiconductor integrated circuit device and the film substrate.

CROSS REFERENCE TO RELATED APPLICATION

This application is a continuation application of U.S. application Ser.No. 09/905,911, filed Jul. 17, 2001, the contents of which areincorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates in general to liquid crystal displaydevices and, in more particular, to a technique usefully applicable toan image signal drive unit (drain driver or drivers) of a liquid crystaldisplay device with multilevel gradation/tone display abilities.

2. Description of the Related Art

Liquid crystal display devices of the active matrix type having anactive element (e.g. thin-film transistor) on a per-pixel basis anddriving this active element to perform a switching operation have widelybeen employed as the display device of a notebook personal computer orthe like.

These active-matrix liquid crystal display (AMLCD) devices are such thatdue to application of an image signal voltage (gradation/tone voltagecorresponding to display data, as will be referred to as gradation/tonevoltage hereinafter) to a pixel electrode via such active element, anycross-talk is absent between respective pixel and thus, it is no longernecessary to employ “special” driving methods for prevention ofcrosstalk unlike simple-liquid crystal display devices, thereby enablingsuccessful achievement of multi-gradation-level or “gray-scale” displayabilities.

As one of the active-matrix liquid crystal display devices, there isknown a TFT liquid crystal display module, which comprises a liquidcrystal display panel of the thin-film transistor (TFT) scheme, alsocalled TFT-LCD panel, drain drivers as disposed on the upper side of theliquid crystal display panel, and gate drivers and an interface sectionas disposed along side faces of the liquid crystal display panel.

FIG. 24 is a block diagram showing a schematic configuration of oneexample of related art TFT liquid crystal display module.

As shown in FIG. 24, a plurality of drain drivers 130 are disposed alonga long edge side of the liquid crystal display panel (TFT-LCD) 10whereas a plurality of gate drivers 140 are laid out along a short edgeside of the liquid crystal display panel 10.

Control signals that are output from a host computer side such as apersonal computer and consist essentially of display data (image signal)of three primary colors of red (R), green (G) and blue (B), a clocksignal(s), a display timing signal(s), and synchronization signals(horizontal sync signal and vertical sync signal) are input to a displaycontrol device (TFT controller) 110 via an interface connector.

A control signal(s) and display data and the like from the displaycontrol device 110 are input to each drain driver 130 via a TFTcontroller substrate 301 and drain driver substrate 302.

In addition, the control signal(s) from the display control device 110will be input to each gate driver 140 through the TFT controllersubstrate 301 and a gate driver substrate 303.

Note that depiction of a wiring layer(s) on or over the TFT controllersubstrate is eliminated in FIG. 24.

Also note that although more than one wiring layer other than the wiringlayer shown in FIG. 24 is also provided on the drain driver substrateand gate driver substrate, only four lines of wiring layers for thedrain driver substrate 302 and only two lines of wiring layers for thegate driver substrate 303 are depicted in FIG. 24.

The drain drivers 130 and gate drivers 140 are constituted fromsemiconductor chips (ICs), wherein these semiconductor chips (ICs) aremounted on a film substrate by either the so-called tape carriertechniques or chip-on-film techniques.

As shown in FIG. 25 a wiring layer (COFA) is formed on the filmsubstrate 310 from the periphery, wherein terminals (BUMP) beingprovided at the periphery of semiconductor chip (IC) are coupled bybonding to this wiring layer (COFA).

Here, drain driver terminals (BUMP) are typically provided along theperipheral portions thereof, one example of which is shown in FIG. 26.

As shown in FIG. 26, input terminals (BUMP2) are disposed along one sidefor enabling connection of wiring leads from the drain driver substrate302 whereas output terminals (BUMP1) are disposed at either theremaining three sides or four peripheral portions including right andleft spaces of a side along which the input terminals (BUMP2) aredisposed.

Additionally output circuits 330 within the drain drivers correspondingto respective output terminals (BUMP1) are typically laid out into alinear array in a way identical to output terminal positions.

Note that such liquid crystal display device has been recited, forexample, in Japanese Patent Laid-Open No. 281930/1997.

In recent years, in liquid crystal display devices such as TFT liquidcrystal display modules, with the increasing demand for larger displayscreen sizes of liquid crystal display panels, they are in the tendencytoward increase in pixel number of a liquid crystal display panel andalso requirement for achievement of higher precision; and, in accordancetherewith, gate signal lines and drain signal lines also increase innumber resulting in a likewise increase in input/output terminal numberof the drain drivers.

For instance, with an XGA-format liquid crystal display panel, therequisite number of drain signal lines is 3,072(=1,024×3 (RGB)).Assuming that drain drivers with 384 output terminals are used, therequired number of drain drivers in the XGA-LCD panel becomes as largeas 8(=3,072/384).

In contrast, with the quest for higher precision further advances up toUXGA specifications, the resultant number of drain signal lines is4,800(=1,600×3 (RGB)). As in the previous case, supposing that draindrivers with the 384 output terminal number are used, the required draindriver number in UXGA-LCD panels becomes 12.5(=4,800/384).

In this way, the higher the precision of liquid crystal display panels,the greater the drain line number per liquid crystal display panel,resulting in an increase in number of drain drivers required.

Whereby the resulting load capacitance of the display control device 110increases accordingly, resulting in occurrence of a problem as to anincapability to drive the drain drivers 130.

In order to prevent the number of drain drivers from changing even whena liquid crystal display panel increases in precision, it should berequired to increase the output terminal number per drain driver.

Generally, semiconductor chips (ICs) making up the drain drivers aresuch that the outer shape thereof is like a laterally elongated plateshape, wherein if output terminals (BUMP) per drain driver increase innumber then it becomes necessary to increase the length of asemiconductor chip (IC) along its lateral direction.

In addition, while semiconductor chips (ICs) are fabricated by cutawayprocesses after having formed a plurality of ones on a singlesemiconductor wafer, the greater the lateral directional length ofsemiconductor chips (ICs) with a further increased length in lateraldirection thereof, the less the number of chips obtainable from a singlewafer, resulting in an undesirable increase in price of a singlesemiconductor chip (IC).

Further, with laterally lengthened semiconductor chips (ICs) with afurther increased length in the lateral direction thereof, there is ananxiety that excessive increase beyond the exposure range can take placewhen forming semiconductor chips (ICs) through the so-calledstep-and-repeat exposure process on the surface of a singlesemiconductor wafer.

To avoid this, it will be required to make use of exposure apparatus ofhigh price, resulting in an increase in price of a single semiconductorchip (IC).

On the other hand, while liquid crystal display devices are under strictrequirement for lower prices, there is a problem that the higher thesemiconductor chip (IC) making up the drain driver 130, the higher theprice of a liquid crystal display device.

In addition, with an increase in drain signal lines, there is a tendencyto inevitable increase in pitch of the output terminals (BUMP1) of draindrivers 130; thus, there is a problem that probing becomes difficultduring screening of semiconductor chips (ICs).

Furthermore, with such increase in drain signal lines, the circuit scaleof a single drain driver 130 tends to grow larger; thus, there is aproblem that a voltage drop-down due to the presence of wiring leadimpedances within semiconductor chip (IC) becomes no longer negligible.

SUMMARY OF THE INVENTION

The invention was made in order to avoid the problems faced with therelated art, and a primary object of the invention is to provide atechnique capable of sufficiently handling or coping with any increasesin pixel number of a liquid crystal display element in the liquidcrystal display device while at the same time enabling achievement of alow price.

It is another object of the invention to provide a technique adaptablefor use in a liquid crystal display device for enabling simplifiedexecution of test/inspection procedures even when the output terminalnumber of a semiconductor integrated circuit device of an image linedrive unit increases.

It is still another object of the invention to provide a technique inthe liquid crystal display device for enabling prevention of anypossible voltage dropdown otherwise occurring due to a wiring layer(s)within a semiconductor integrated circuit device even when the outputterminal number of the semiconductor integrated circuit device of imageline drive unit increases.

These objects and new features of the invention will become apparentfrom the description of the specification and the accompanying drawings.

A summary of representative ones of the inventions as disclosed hereinwill be explained in brief below.

To be brief, the invention is concerned with a liquid crystal displaydevice which comprises a liquid crystal display element having aplurality of pixels and a plurality of image signal lines for applying agradation/tone voltage corresponding to display data to the plurality ofpixels and image signal line drive unit for supplying to each the imagesignal line a gradation/tone voltage corresponding to display data,wherein the image line drive unit has more than one semiconductorintegrated circuit device, and the semiconductor integrated circuitdevice has a first output terminal section which is provided for exampleat a central portion in a short side direction of the semiconductorintegrated circuit device and also in a longitudinal direction of thesemiconductor integrated circuit device, and a pair of output circuitunits provided on both sides of the first output terminal section in ashort side direction of the semiconductor integrated circuit device forgenerating a gradation/tone voltage to be supplied to each image signalline.

In addition, the invention is concerned with a liquid crystal displaydevice which comprises a liquid crystal display element having aplurality of pixels and a plurality of image signal lines for applying agradation/tone voltage corresponding to display data to the plurality ofpixels and image signal line drive unit for supplying to each imagesignal line a gradation/tone voltage corresponding to display data,wherein the image line drive unit has a plurality of semiconductorintegrated circuit devices, and each semiconductor integrated circuitdevice has an input circuit unit as provided in a short side directionof the semiconductor integrated circuit device, a first output terminalsection provided on both sides of the input circuit unit in alongitudinal direction of the semiconductor integrated circuit deviceand also provided in the longitudinal direction of the semiconductorintegrated circuit device, and a pair of output circuit units providedon both sides of the first output terminal section in the short sidedirection of the semiconductor integrated circuit device, for generatinga gradation/tone voltage to be supplied to each image signal line.

Additionally, according to one preferred form of the invention, in aregion other than the first output terminal section and the outputcircuit unit, is provided a second output terminal section as providedalong a peripheral portion of two short sides of at least thesemiconductor integrated circuit device.

In addition, according to one preferred form of the invention, the pairof output circuit units are such that a positive polarity output circuitunit for generation of a positive gradation/tone voltage and a negativepolarity output circuit unit for generation of a negative gradation/tonevoltage are provided alternately.

In addition, according to one preferred form of the invention, oneoutput circuit unit of the pair of output circuit units is provided witha positive polarity output circuit unit for generation of a positivegradation/tone voltage, and a remaining output circuit unit of the pairof output circuit units is provided with a negative polarity outputcircuit unit for generation of a negative gradation/tone voltage.

In addition, according to one preferred form of the invention, theoutput circuit unit has a buffer circuit, a decoder circuit, a datalatch circuit, and a shift register circuit, wherein the buffer circuit,decoder circuit, data latch circuit and shift register circuit aredisposed from the first output terminal section toward the short sidedirection of the semiconductor integrated circuit device in an order ofthe buffer circuit, decoder circuit, data latch circuit and shiftregister circuit.

Additionally, the invention is concerned with a liquid crystal displaydevice comprising a liquid crystal display element having a plurality ofpixels and a plurality of image signal lines for applying agradation/tone voltage corresponding to display data to the plurality ofpixels and image signal line drive unit for supplying to each imagesignal line a gradation/tone voltage corresponding to display data,wherein the image line drive unit has a plurality of semiconductorintegrated circuit devices, and each semiconductor integrated circuitdevice has an input circuit unit as provided in a short side directionof the semiconductor integrated circuit device, a plurality of outputterminal sections provided on both sides of the input circuit unit in alongitudinal direction of the semiconductor integrated circuit deviceand also provided in the longitudinal direction of the semiconductorintegrated circuit device, and a pair of output circuit units providedper each output terminal section on both sides of each output terminalsection in the short side direction of the semiconductor integratedcircuit device for generating a gradation/tone voltage to be supplied toeach image signal line.

Additionally, the invention is concerned with a liquid crystal displaydevice comprising a liquid crystal display element having a plurality ofpixels and a plurality of image signal lines for applying agradation/tone voltage corresponding to display data to the plurality ofpixels and image signal line drive unit for supplying to each imagesignal line a gradation/tone voltage corresponding to display data,wherein the image line drive unit has a film substrate with a pluralityof wiring layers formed thereover and more than one semiconductorintegrated circuit device as mounted on the film substrate, thesemiconductor integrated circuit device has in a region other thanperipheral part of the semiconductor integrated circuit device aplurality of bump electrodes as provided in the longitudinal directionof the semiconductor integrated circuit device, and part of the wiringlayers of the film substrate is connected at one end to each bumpelectrode of the semiconductor integrated circuit device and alsoprovided to extend from the one end up to the peripheral part of thefilm substrate while letting part including the one end be covered bythe semiconductor integrated circuit device.

Additionally, the invention is concerned with a liquid crystal displaydevice comprising a liquid crystal display element having a pair ofsubstrates and a liquid crystal layer interposed between the pair ofsubstrates and also having a plurality of pixels and a plurality ofimage signal lines for application of a gradation/tone voltagecorresponding to display data to the plurality of pixels of the liquidcrystal layer, and an image signal drive unit for supplying agradation/tone voltage corresponding to display data to each imagesignal line, wherein the image signal line drive unit has more than onesemiconductor integrated circuit device as mounted on one substrate ofthe pair of substrates, the semiconductor integrated circuit device hasin a region other than peripheral part of the semiconductor integratedcircuit device a plurality of bump electrodes as provided in alongitudinal direction of the semiconductor integrated circuit device,part of the image signal lines being formed on the one substrate is suchthat a terminal section is connected to each bump electrode of thesemiconductor integrated circuit device while letting a region includingthe terminal section be covered by the semiconductor integrated circuitdevice.

In addition, according to one preferred form of the invention, theplurality of bump electrodes are formed into a plurality of columns inthe longitudinal direction of the semiconductor integrated circuitdevice.

In addition, according to one preferred form of the invention, more thanone bump electrode of a partial column of the plurality of columns isarranged so that a length in the longitudinal direction of thesemiconductor integrated circuit device is longer than a length of abump electrode in the longitudinal direction of the semiconductorintegrated circuit device, the bump electrode belonging to a column in adirection in which the wiring layer of the film substrate is extendedthan the column.

Additionally, the invention is concerned with a liquid crystal displaydevice comprising a liquid crystal display element having a plurality ofpixels and a plurality of image signal lines for applying agradation/tone voltage corresponding to display data to the plurality ofpixels and image signal line drive unit for supplying to each imagesignal line a gradation/tone voltage corresponding to display data,wherein the image line drive unit has a film substrate with a pluralityof wiring layers formed thereover and more than one semiconductorintegrated circuit device as mounted on the film substrate, thesemiconductor integrated circuit device has a plurality of bumpelectrodes, and portions of the plurality of bump electrodes areelectrically connected together by a wiring layer as provided at thefilm substrate.

Additionally, the invention is concerned with a liquid crystal displaydevice comprising a liquid crystal display element having a plurality ofpixels and a plurality of image signal lines for applying agradation/tone voltage corresponding to display data to the plurality ofpixels, and an image signal line drive unit for supplying to each imagesignal line a gradation/tone voltage corresponding to display data,wherein the image line drive unit has a film substrate with a pluralityof wiring layers formed thereover and more than one semiconductorintegrated circuit device as mounted on the film substrate, thesemiconductor integrated circuit device has a plurality of bumpelectrodes, portions of the plurality of bump electrodes areelectrically connected together by a wiring layer as provided at thefilm substrate, and an input signal is externally applied to the wiringlayer for connection between the bump electrodes.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram schematically showing a configuration of aliquid crystal display module of the TFT type to which the invention isapplied;

FIG. 2 is a diagram showing an equivalent circuit of one example of theliquid crystal display panel shown in FIG. 1;

FIG. 3 is a diagram showing an equivalent circuit of another example ofthe liquid crystal display panel shown in FIG. 1;

FIG. 4 is a diagram for explanation of the polarity of a liquid crystaldrive voltage as output from a drain driver to a drain signal line (D)in case a dot inversion method is used as a drive method of the liquidcrystal display module;

FIG. 5 is a block diagram schematically showing a configuration of oneexample of the drain driver shown in FIG. 1;

FIG. 6 is a block diagram used to explain more practically aconfiguration of one example of the drain driver shown in FIG. 5;

FIG. 7 is a block diagram used to explain more practically aconfiguration of one example of the drain driver shown in FIG. 5;

FIG. 8 is a circuit diagram showing a schematic configuration of oneexample of a high-voltage decoder circuit and low-voltage decodercircuit shown in FIGS. 6 and 7;

FIG. 9 is a circuit diagram showing a schematic arrangement of oneexample of the high-voltage amplifier circuit and low-voltage amplifiercircuit shown in FIGS. 6 and 7;

FIG. 10 is a circuit diagram showing a differential amplifier circuitfor use in an operational amplifier of the low-voltage amplifier circuitshown in FIG. 9;

FIG. 11 is a circuit diagram showing a differential amplifier circuitfor use in an operational amplifier of the high-voltage amplifiercircuit shown in FIG. 9;

FIG. 12 is a circuit diagram showing a circuit configuration of aselector circuit as one example of an output selection circuit shown inFIG. 7;

FIG. 13 is a diagram showing a layout of internal circuitry of asemiconductor chip (IC) making up the drain driver of Embodiment 1 ofthe invention;

FIG. 14 is a diagram showing a layout of a wiring layer (COFA) on a filmsubstrate in accordance with Embodiment 1 of the invention;

FIG. 15 is a diagram showing a layout of internal circuitry of asemiconductor chip (IC) constituting a drain driver of Embodiment 2 ofthe invention;

FIG 16 is a pictorial diagram showing a structure of a related knowndecoder circuit within a semiconductor chip (IC);

FIG. 17 is a pictorial diagram showing a structure of a decoder circuitwithin a semiconductor chip (IC) in accordance with Embodiment 2 of theinvention;

FIG. 18 is a diagram showing a layout of internal circuitry of asemiconductor chip (IC) constituting a drain driver of Embodiment 3 ofthe invention;

FIG. 19 is a diagram showing a layout of a wiring layer (COFA) on a filmsubstrate of Embodiment 3 of the invention;

FIG. 20 is a diagram for explanation of disposal of output terminals(BUMP1) of a semiconductor chip (IC) making up a drain driver ofEmbodiment 4 of the invention;

FIG. 21 is a diagram for explanation of part of a terminal (BUMP) of asemiconductor chip (IC) making up a drain driver of Embodiment 5 of theinvention along with part of a wiring layer (COFB) that is formed on afilm substrate;

FIG. 22 is a diagram for explanation of a modified example of FIG. 21;

FIG. 23 is a diagram for explanation of a modification of FIG. 21;

FIG. 24 is a block diagram showing a schematic configuration of oneexample of a related art TFT liquid crystal display module;

FIG. 25 is a diagram showing a related art film substrate with draindrivers mounted thereon; and

FIG. 26 is a diagram showing a configuration of the terminal section ofa related art drain driver.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Preferred embodiments of the invention will be explained with referenceto the accompanying drawings below.

Note that in all the drawings used to explain the embodiments of theinvention, those having same functions will be designated by samereference characters and any repetitive explanation thereof will beeliminated.

Embodiment 1

<Basic Arrangement of Display Device to Which the Invention is Applied>

FIG. 1 is a block diagram schematically showing an arrangement of aliquid crystal display module of the TFT type to which the invention isapplied.

The liquid crystal display module (LCM) shown in FIG. 1 is such thatdrain drivers 130 are disposed along one side on the long edge side of aliquid crystal display panel (TFT-LCD) 10 whereas gate drivers 140 arelaid out along one side on the short edge side of the liquid crystaldisplay panel 10.

The liquid crystal display panel 10 is constituted from 1,600 x 800 x 3picture elements, for example.

Additionally here, a single picture element is to be understood to meanone pixel (Pix) of red (R), green (G) and blue (B).

Control signals being output from a host computer side such as apersonal computer, which signals consist essentially of three-colordisplay data (image signal) of red (R), green (G) and blue (B), clocksignal, display timing signal and synchronbization signals (horizontalsync signal, vertical sync signal) are input via an interface connectorto a display control device (TFT controller) 110.

In the illustrative embodiment an interface unit 100 is mounted on theabove-noted TFT controller substrate 301 shown in FIG. 24, the draindrivers 130 are mounted on the drain driver substrate 302 shown in FIG.24, and the gate drivers 140 are on the gate driver substrate 303 shownin FIG. 24.

Here, semiconductor chips (ICs) making up the drain drivers 130 and gatedrivers 140 are mounted on a film substrate 310 by either so-called tapecarrier package techniques or chip-on-film techniques.

Note that the above semiconductor chips (ICs) may alternatively bemounted directly on one transparent substrate of the liquid crystaldisplay panel 10 by chip-on-glass technologies.

<Arrangement of Liquid Crystal Display Panel 10 Shown in FIG. 1>

FIG. 2 is a diagram showing an equivalent circuit of one example of theliquid crystal display panel 10 shown in FIG. 1.

As shown in this FIG. 2, the liquid crystal display panel 10 has aplurality of picture elements or pixels that are formed into a matrixform.

Each pixel is disposed within a cross-over or “intersection” regiondefined by two neighboring signal lines (drain signal lines (D) or gatesignal lines (G)) and two neighboring signal lines (gate signal lines(G) or drain signal lines (D)).

Each pixel has thin-film transistors (TFT1, TFT2), wherein sourceelectrodes of such thin-film transistors (TFT1, TFT2) are connected to apixel electrode (ITO1).

Additionally, since a liquid crystal layer is provided between the pixelelectrode (ITO1) and a common electrode (ITO2), a liquid crystalcapacitor (CLC) is equivalently connected between the pixel electrode(ITO1) and common electrode (ITO2).

Further, an additional capacitor (CADD) is connected between the sourceelectrodes of the thin-film transistors (TFT1, TFT2) and a gate signalline (G) of the previous stage.

FIG. 3 is a diagram showing an equivalent circuit of another example ofthe liquid crystal display panel 10 shown in FIG. 1.

While in the example shown in FIG. 2 the additional capacitor (CADD) isformed between the pre-stage gate signal line (G) and the sourceelectrode, the equivalent circuit of the example shown in FIG. 3 isdifferent therefrom in that the storage capacitor (CSTG) is formedbetween a common signal line (CN) and source electrode.

Although the invention is applicable to the both, the former scheme issuch that a pre-stage gate signal line (G) pulse jumps into the pixelelectrode (ITO1) through the additional capacitor (CADD) whereas thelatter scheme is such that such jump-in will no longer take placeenabling achievement of more excellent displaying.

Note that FIGS. 2 and 3 show equivalent circuits of liquid crystaldisplay panels of the type employing longitudinal electric fieldschemes. In FIGS. 2-3, “AR” is a display region.

Additionally, although FIGS. 2-3 are circuit diagrams, illustration ismade in a way corresponding to actually implementable geometric layouts.

In the liquid crystal display panels 10 shown in FIGS. 2-3, drainelectrodes of thin-film transistors (TFT1, TFT2) of each of the pixelsthat are disposed in a column direction are connected to drain signallines (D) respectively, wherein each drain signal line (D) is connectedto a drain driver 130 which applies a gradation/tone voltage to liquidcrystal of each pixel in the column direction.

In addition, gate electrodes of thin-film transistors (TFT1, TFT2) ineach of the pixels that are disposed in a row direction are connected togate signal lines (G) respectively, wherein each gate signal line (G) isconnected to a gate driver 140 which supplies within one horizontalscanning time period a scan drive voltage (positive bias voltage ornegative bias voltage) to the gate electrodes of the thin-filmtransistors (TFT1, TFT2) of each pixel in the row direction.

<Arrangement and Operation Summary of Interface Unit 100 Shown in FIG.1>

The interface unit 100 shown in FIG. 1 is made up from a display controldevice 110 and a power supply circuit 120.

The display control device 110 is formed of a single semiconductorintegrated circuit (LSI), which is operable to control and drive thedrain drivers 130 and gate drivers 140 on the basis of display data(R-G-B) and respective display control signals including but not limitedto a clock signal, display timing signal, horizontal sync signal andvertical sync signal as transmitted from a computer main body side.

Upon inputting of the display timing signal, the display control device110 judges it as a display startup position and then outputs a startpulse (display data accept start signal) to a first drain driver 130 viaa signal line 135 and further outputs the received display data ofsimple one column to drain drivers 130 through a display data bus line133.

In such an event the display control device 110 outputs via a signalline 131 a display data latch-use clock (CL2) (simply referred to as“clock (CL2)” hereinafter) which is a display control signal forlatching display data at a data latch circuit of each drain driver 130.

It should be noted that even in this embodiment also, the controlsignals and display data or the like from the display control device 110are input to each drain driver 130 via the TFT controller substrate 301and drain driver substrate 302 in the above-stated way shown in FIG. 24.

Display data from the computer main body side is of 6 bits for exampleand will be transferred on a per-unit time basis with single pixel beingas a unit, that is, with respective data bits of red (R), green (G) andblue (B) being combined together into one set.

In addition a latching operation of the data latch circuit at the firstdrain driver 130 will be controlled in response to the start pulse asinput to the first drain driver 130.

Upon termination of the latch operation of the data latch circuit atthis first drain driver 130, the start pulse is input from the firstdrain driver 130 to a second drain driver 130 for control of a latchoperation of a data latch circuit at the second drain driver 130.

Thereafter, a similar operation will be repeated for controlling thelatch operation of a data latch circuit at each drain driver 130,thereby preventing incorrect display data from being written into thedata latch circuit.

Upon termination of inputting of the display timing signal oralternatively when a predefined length of time is elapsed from a timepoint at which the display timing signal was inputted, the displaycontrol device 110 regards it as termination of display data of onehorizontal portion and then outputs to each drain driver 130 via asignal line 132 an output timing control clock (CL1) (simply referred toas clock (CL1) hereafter) which is a display control signal foroutputting the display data being stored or accumulated at the datalatch circuit at each drain driver 130 to more than one drain signalline (D) of the liquid crystal display panel 10.

Additionally when the first display timing signal is input after inputof a vertical sync signal, the display control device 110 judges it as afirst display line and then outputs a frame start instruction signal tothe gate driver(s) 140 via a signal line 142.

Further, the display control device 110 outputs based on a horizontalsync signal a clock (CL3) that is a shift clock of one horizontal scantime period to the gate driver(s) 140 via a signal line 141 forsequential application of a positive bias voltage to each gate signalline (G) of the liquid crystal display panel 10 once at a time wheneverone horizontal scan period has elapsed.

Thus, a plurality of thin-film transistors (TFT1, TFT2) connected toeach gate signal line (G) of the liquid crystal display panel 10 arerendered conductive within the one horizontal scan time period.

With the above operation, an image will be displayed on the liquidcrystal display panel 10.

<Arrangement of Power Supply Circuit 120 Shown in FIG. 1>

The power supply circuit 120 shown in FIG. 1 is configured from apositive voltage generation circuit 121, a negative voltage generatorcircuit 122, a common electrode (opposite or “counter” electrode)voltage generator circuit 123, and a gate electrode voltage generatorcircuit 124.

The positive voltage generator circuit 121 and negative voltagegenerator circuit 122 are each formed of a serial resistance voltagedivider circuit, wherein the positive voltage generator circuit 121 isdesigned to output a five-value gradation/tone reference voltage of thepositive polarity (V″0 to V″4) whereas the negative voltage generatorcircuit 122 outputs a five-value gradation/tone reference voltage of thenegative polarity (V″5 to V″9).

These five-value gradation/tone reference voltage of the positivepolarity (V″0 to V″4) and five-value gradation/tone reference voltage ofthe negative polarity (v“5 to V″9) are supplied to each drain driver130.

In addition, a polarity inversion signal (AC-modified signal M) from thedisplay control device 110 is also supplied to each drain driver 130 viaa signal line 134.

The common electrode voltage generator circuit 123 generates a drivevoltage to be applied to a common electrode (ITO2) whereas the gateelectrode voltage generator circuit 124 generates drive voltages(positive bias voltage and negative bias voltage) being applied to thegate electrodes of thin-film transistors (TFT1, TFT2).

<AC-Modified Drive Method of Liquid Crystal Display Module Shown in FIG.1>

Generally the liquid crystal layer is such that if the same voltage (DCvoltage) is being applied a long time then the liquid crystal layer'sinclination or tilt is fixed resulting in occurrence of after-imagephenomena, which in turn causes a decrease in lifetime of the liquidcrystal layer.

To avoid this, the liquid crystal display module is designed so that anyvoltage being applied to the liquid crystal layer is converted to anAC-like voltage—say, AC-modified-once at a time whenever a predefinedlength of time has elapsed; more specifically, let a voltage beingapplied to a pixel electrode potentially change toward the positivevoltage side/negative voltage side in units of predetermined timeperiods with the voltage as applied to a common electrode being as astandard or “reference.”

Known drive methodology for applying such AC-modified voltage to thisliquid crystal layer includes two methods: a common symmetry method, andcommon inversion method.

The common inversion method is the method that alternately inverts thevoltage being applied to the common electrode and the voltage applied topixel electrode to have positive and negative polarities. in contrast,the common symmetry method is the method that makes the voltage beingapplied to the common electrode constant in potential while alternatelyinverting the voltage as applied to the pixel electrode into positiveand negative polarities with the voltage applied to the common electrodebeing as a reference.

Although the common symmetry method has a disadvantage that theamplitude of a voltage being applied to pixel electrode (ITO1) becomestwo times greater than that in the common inversion method resulting inpresence of an incapability to make use of any low breakdown-voltagedrivers unless “special” liquid crystals low in threshold voltage isnewly developed, it is possible to use either dot inversion methods orN-line inversion methods excellent both in lower power consumption andin higher display quality.

One typical dot inversion method will next be explained below.

FIG. 4 is a diagram used to explain the polarity of a liquid crystaldrive voltage (i.e. gradation/tone voltage being applied to pixelelectrode (ITO1)) that is output from a drain driver 130 onto itsassociative drain signal line (D) in case the dot inversion method isused as a liquid crystal display module driving method.

As shown in FIG. 4, in the case where the dot inversion method is usedas the liquid crystal display module drive method, at an odd-numberedline of an odd-numbered frame for example, a liquid crystal drivevoltage (indicated by ”●” in FIG. 4) that is of the negative polarityrelative to a liquid crystal drive voltage (VCOM) to be applied to thecommon electrode (ITO2) is applied from a drain driver 130 to anodd-numbered drain signal line (D) whereas a liquid crystal drivevoltage (indicated by “∘” in FIG 4) that is positive in polarityrelative to the liquid crystal drive voltage (VCOM) being applied to thecommon electrode (ITO2) is applied to an even-numbered drain signal line(D).

Further, at an even-numbered line of the odd-numbered frame, a liquidcrystal drive voltage of the positive polarity is applied from draindriver 130 to odd-numbered drain signal line (D) while letting a liquidcrystal drive voltage of the negative polarity be applied toeven-numbered drain signal line (D). In addition, the polarity per eachline is inverted in units of frames. More specifically, as shown in FIG.4, at an odd-numbered line of even-numbered frame, a positive liquidcrystal drive voltage is applied from drain driver 130 to odd-numbereddrain signal line (D) whereas a negative liquid crystal drive voltage isapplied to even-numbered drain signal line (D).

Further, at even-numbered line of even-numbered frame, a negative liquidcrystal drive voltage is applied from drain driver 130 to odd-numbereddrain signal line (D) whereas a positive liquid crystal drive voltage isapplied to even-numbered drain signal line (D).

The use of this dot inversion method permits voltages being applied toneighboring drain signal lines (D) to have reversed polarities, which inturn makes it possible for currents flowing into common electrodes(ITO2) and/or thin-film transistor (TFT1, TFT2) gate electrodes tocancel out each other between neighboring ones, resulting in a decreasein resultant power consumption.

Another advantage lies in an ability to render the common electrode(ITO2)'s voltage level stable to thereby greatly suppress or minimizedisplay quality reducibilities because of the fact that the commonelectrode (ITO2)-flowing current becomes less thereby preventing voltagedropdown from becoming greater.

<Arrangement of Drain Driver 130 Shown in FIG. 1>

FIG. 5 is a block diagram schematically showing a configuration of oneexample of the drain driver 130 shown in FIG. 1.

Note that the drain driver 130 is formed of a single semiconductorintegrated circuit (LSI).

In FIG. 5 a gradation/tone voltage generator circuit 151 generates apositive gradation/tone voltage with 64 gradation levels or “grayscales” based on the positive-polarity five-value gradation/tonereference voltage (V″0 to V″4) as input from the positive voltagegenerator circuit 121 and also a negative gradation/tone voltage with 64gray scales based on the negative five-value gradation/tone referencevoltage (V″5 to V″9) being input from the negative voltage generatorcircuit 122, and then outputs the respective 64-gray-scalegradation/tone voltages of the positive and negative polarities to adecoder circuit 157 through a voltage bus line(s).

Additionally a shift register circuit 153 generates a data accept signalbased on a shift clock synchronized with a clock (CL2) being output froma clock control circuit 152 and then outputs it to a latch circuit (1)155.

Display data to be input from the display control device 110 istemporarily latched at an input latch circuit 154.

This input latch circuit 154 latches the display data based on a clockfrom a clock control circuit 152.

The latch circuit (1) 155 is operable based on the data accept signal asoutput from shift register circuit 153 to latch an outputline-equivalent number of 6-bit display data per each color being outputfrom the input latch circuit 154 in a way synchronous with the clock(CL2) as input from display control device 110.

A latch circuit (2) 156 latches the display data within the latchcircuit (1) 155 in accordance with a clock (CL1) being input from thedisplay control device 110.

The display data as taken into or “imported” to this latch circuit (2)156 will then be input to the decoder circuit 157 via internallevel-shift circuitry.

The decoder circuit 157 selects from either the positive 64-gray-scalegradation/tone voltage or negative 64-gray-scale gradation/tone voltagea single gradation/tone voltage corresponding to the display data(voltage indicative of the one selected from among 64 gradation levels)and then outputs it to a buffer circuit 158.

The buffer circuit 158 amplifies (current-amplifies) the inputgradation/tone voltage for output to each drain signal line (D).

FIG. 6 is a block diagram that is used to more practically explain aconfiguration of one example of the drain driver 130 shown in FIG. 5.

In FIG. 6, reference numeral “153” designates the shift register circuitshown in FIG. 5, and 157 denotes the decoder circuit shown in FIG. 5,wherein a data latch unit 262 represents latching of the latch circuit(1) 155 and latch circuit (2) 156 shown in FIG. 5 whereas a level shiftcircuit 263 indicates a level-shift circuit within the latch circuit (2)shown in FIG. 5.

Further, an amplifier circuit 264 and an output selector circuit 265 forchanging over or switching an output of the amplifier circuit 264constitute the buffer circuit 157 shown in FIG. 5.

Here, a display data selector circuit 261 and the output selectorcircuit 265 are controlled based on a polarity inversion signal (M).

In addition, Y1, Y2, Y3, Y4, Y5 and Y6 designate first, second, third,fourth, fifth and sixth drain signal lines (D), respectively.

In the drain driver 130 shown in FIG. 6, the display data selectorcircuit 261 is operable to switch a data accept signal as input by thedisplay data selector circuit 261 to the data latch unit 262 (in moredetail, latch circuit (1) 155 shown in FIG. 5) and then input continuousdisplay data to the neighboring data latch units 262.

The decoder circuit 157 is formed of a high-voltage decoder circuit 251which selects from among positive-polarity gradation/tone voltages of 64gray scale levels being supplied from the gradation/tone voltagegenerator circuit 151 a gradation/tone voltage of the positive polaritythat corresponds to display data to be output from each data latchcircuit 262 (in greater detail, latch circuit (2) 156 shown in FIG. 5),and a low-voltage decoder circuit 252 which selects from among negativegradation/tone voltages of 64 gray scales being supplied from thegradation/tone voltage generator circuit 151 a gradation/tone voltage ofthe negative polarity that corresponds to display data to be output fromeach data latch circuit 262.

The high-voltage decoder circuit 251 and low-voltage decoder circuit 252are provided in units of neighboring data latch units 262.

The amplifier circuit 264 is formed of a high-voltage amplifier circuit271 and low-voltage amplifier circuit 272.

A positive gradation/tone voltage as generated at the high-voltagedecoder circuit 251 is input to the high-voltage amplifier circuit 271,which then outputs a positive gradation/tone voltage.

A negative gradation/tone voltage as generated at the low-voltagedecoder circuit 252 is input to the low-voltage amplifier circuit 272,which then outputs a negative gradation/tone voltage.

With the dot inversion method, gradation/tone voltages of continuousdisplay data will become reversed in polarity to each other while aserial array layout or “queue” of amplifier circuits 264 becomes thehigh-voltage amplifier circuit 271→low-voltage amplifier circuit272→high-voltage amplifier circuit 271→low-voltage amplifier circuit272; thus, it becomes possible to output either positive or negativegradation/tone voltage to each drain signal line (D) by causing thedisplay data selector circuit 261 to switch display data being input tothe data latch unit 262 and then input continuous display data toalternately neighboring data latch units 262 while in a way synchronizedtherewith letting the output selector circuit 265 switch an outputvoltage as output from either the high-voltage amplifier circuit 271 orlow-voltage amplifier circuit 272 and then output it to more than onedrain signal line (D) from which the gradation/tone voltage ofcontinuous display data will be output for example, a first drain signalline (Y1) and second drain signal line (Y2).

FIG. 7 is a block diagram used to more practically explain theconfiguration of another example of the drain driver 130 shown in FIG.5.

This example shown in FIG. 7 is the one which is arranged to utilize thefact that gradation/tone voltages of neighboring display data ofrespective colors become reversed in polarity to each other for causingthe display data selector circuit 261 to switch display data being inputto the data latch unit 262 and then input continuous display data ofrespective colors to neighboring data latch units 262 while in a waysynchronized therewith letting the output selector circuit 265 switch anoutput voltage as output from either the high-voltage amplifier circuit271 or low-voltage amplifier circuit 272 and then output it to certaindrain signal lines (D) from which the gradation/tone voltages ofcontinuous display data of respective colors will be output-e.g. thefirst drain signal line (Y1) and fourth drain signal line (Y4).

With the examples shown in FIGS. 6 and 7, these are aimed at reductionin chip size of semiconductor chips (ICs) by reducing the requisitenumber of low-voltage circuits and high-voltage circuits only to thatcorresponding to ½ of the terminal number, rather than setting it at thetotal number of output terminals involved.

FIG. 8 is a circuit diagram showing a schematic configuration of oneexample of the high-voltage decoder circuit 251 and low-voltage decodercircuit 252 shown in FIGS. 6 and 7.

With the example shown in FIG. 8, the high-voltage decoder circuit 251or the low-voltage decoder circuit 252 shown in FIG. 6 is constitutedfrom a transistor array or “train” (TRP2, TRP3) with a serial connectionof enhancement MOS transistors and depression MOS transistors.

The high-voltage amplifier circuit 271 and low-voltage amplifier circuit272 shown in FIGS. 6-7 are each formed of a voltage follower circuit,wherein the inverting input terminal (BUMP) (−) and output terminal(BUMP) of an operational amplifier or “ope-amp” (OP) are directlyconnected together with its non-inverting input terminal (BUMP) (+)being used as an input terminal (BUMP) as shown in FIG. 9 by way ofexample.

Here, the ope-amp (OP) for use in the low-voltage amplifier circuit 272is formed for example of a differential amplifier circuit such as shownin FIG. 10; further, the ope-amp (OP) used for the high-voltageamplifier circuit 271 is formed for example of a differential amplifiercircuit shown in FIG. 11.

FIG. 12 is a circuit diagram showing a circuit configuration of oneselector circuit of one example of the output selector circuit 265 shownin FIG. 7.

As shown in FIG. 12, one selector circuit of the output selectorcircuits 265 shown in FIG. 7 has a PMOS transistor (PM1) that isconnected between the high-voltage amplifier circuit 271 and n-th drainsignal (Yn), a PMOS transistor (PM2) being connected between thehigh-voltage amplifier circuit 271 and (n+3)th drain signal (Yn+3), anNMOS transistor (NM1) connected between the low-voltage amplifiercircuit 272 and (n+3)th drain signal (Yn+3), and an NMOS transistor(NM2) coupled between the low-voltage amplifier circuit 272 and n-thdrain signal (Yn).

The PMOS transistor (PM1) has its gate electrode to which an output of aNOR circuit (NOR1) that has been inverted by an inverter (INV) is inputafter having been level-shifted by a level shift circuit (LS) whereasthe PMOS transistor (PM2) has its gate electrode to which an output of aNOR circuit (NOR2) that has been inverted by an inverter (INV) is inputafter having been level-shifted by a level shift circuit (LS).

Similarly an output of a NAND circuit (NAND2) which has been inverted byan inverter (INV) is input to the gate electrode of the NMOS transistor(NM1) after having level-shifted by level shift circuit (LS) whereas anoutput of a NAND circuit (NAND1) that has been inverted by inverter(INV) is input to the gate electrode of the NMOS transistor (NM2) afterhaving level-shifted by level shift circuit (LS).

Here, a polarity inversion signal (M) is input to the NAND circuit(NAND1) and NOR circuit (NOR1) while a polarity inversion signal (M)which has been inverted by inverter (INV) is input to the NAND circuit(NAND2) and NOR circuit (NOR2).

In addition an output enable signal (ENB) is input to the NAND circuits(NAND1, NAND2) whereas an output enable signal (ENB) that has beeninverted by inverter (INV) is input to the NOR circuits (NOR1, NOR2).

A truth value table of the NAND circuits (NAND1, NAND2) and NOR circuits(NOR1, NOR2) is shown in Table 1 along with ON/OFF states of respectiveMOS transistors (PM1, PM2, NM1, NM2) at that time. TABLE 1 ENB M NOR1PM1 NAND2 NM1 NAND1 PM2 NOR2 NM2 L * L OFF H OFF H OFF L OFF H H L OFF HOFF L ON H ON L H ON L ON H OFF L OFFSymbol “*” represents irrelevancy to AC-modified signal (M).

As apparent from Table 1 , when the output enable signal (ENB) is at“Low” level (referred to hereinafter as “L” level) the NAND circuits(NAND1, NAND2) are set at “High” level (H level) whereas the NORcircuits (NOR1, NOR2) are at L level causing respective MOS transistors(PM1, PM2, NM1, NM2) to be in the OFF state.

Upon switching of a scan line, both the high-voltage amplifier circuit271 and low-voltage amplifier circuit 272 are in unstable states.

This output enable signal (ENB) is provided in order to prevent anoutput of each amplifier circuit (271, 272) from being output onto eachdrain signal line (D) within scan line switching or changeover periods.

It should be noted that although with this embodiment the invertedsignal of a clock (CL1) is used as this output enable signal (ENB), itwill also be possible to internally generate it through a process ofcounting the clock (CL2) or other similar suitable processes.

Also note that as apparent from Table 1 also, when the output enablesignal (ENB) is at H level, each NAND circuit (NAND1, NAND2) is ateither H level or L level in accordance with the polarity inversionsignal (M)'s H level or L level while allowing each NOR circuit (NOR1,NOR2) to be at H level or L level.

Whereby, the PMOS transistor (PM1) and NMOS transistor (NM1) turn on oroff and the PMOS transistor (PM2) and NMOS transistor (NM2) turn on oroff causing an output of the high-voltage amplifier circuit 271 to beoutput to the drain signal line (Yn+3) with an output of the low-voltageamplifier circuit 272 being output to drain signal line (Yn), oralternatively causing the output of high-voltage amplifier circuit 271to be output to the drain signal line (Yn) with the output oflow-voltage amplifier circuit 272 being output to drain signal line(Yn+3).

<Characteristic Arrangement of Liquid Crystal Display Module of ThisEmbodiment>

FIG. 13 is a diagram showing a layout of internal circuitry of asemiconductor chip (IC) making up the drain driver 130 of thisembodiment.

As shown in FIG. 13, this embodiment is characterized in that aspecified number of output circuit blocks each of which consistsessentially of the shift register circuit 153, data latch unit 262,decoder circuit 157 and buffer circuit 158 are stacked over each otherinto two stages in the short side direction of semiconductor chip (IC),the number corresponding to an output terminal number.

And, as shown in FIG. 13, an output terminal (bump electrode) region (a)20 is provided at a central portion in the short side direction ofsemiconductor chip (IC) while letting the output circuit blocks that areso disposed as to be stacked over each other into the two stages beprovided in an order of sequence, from this output terminal region (a)20, of the buffer circuit 158, decoder circuit 157, data latch unit 262and shift register circuit 153.

Additionally an input circuit/lead wiring region 23 is provided at acentral portion along the longitudinal direction of the semiconductorchip (IC) for supplying display data and a clock(s) to the outputcircuit blocks that are disposed so that they are stacked into twostages.

In this way, with the illustrative embodiment, disposing those outputterminal portions of the same shape in an adjacent region (outputterminal region (a)) makes it possible to delete any dead spaces, whichin turn enables reduction or shrinkage of the area of such outputterminal section. Additionally reference numeral “22” denotes an inputterminal region.

With this embodiment, in view of the fact that the output circuit blocksare disposed so that these are stacked over each other into two stages,the shift register circuit 153 is disposed on a per-stage basis.

Due to this, the drain driver 130 of this embodiment is such that ashift register circuit formation region increases when compared to thedrain drivers 130 shown in FIGS. 6-7.

However, in light of the fact that the shift register circuit 153 islow-voltage circuitry manufacturable by low breakdown voltage processesand is small in circuit scale, even if it becomes two times greater, theresultant increase in area stays negligible.

In this way, with this embodiment, since the gradation/tone voltageoutput circuit section which occupies large part of the semiconductorchip (IC) making up the drain driver 130 is specifically arranged to besubdivided into two parts, it is possible to make the semiconductor chip(IC)'s length in the longitudinal direction thereof almost half (½) incomparison with an arrangement for letting such circuits be linearlydisposed in the chip's longitudinal direction.

Note here that in this embodiment, the length of the semiconductor chip(IC) in its short side direction becomes virtually two times greaterwhen compared to an arrangement that the gradation/tone voltage outputcircuits shown in FIG. 26 are linearly disposed in the chip'slongitudinal direction.

To be brief, with this embodiment, an outer shape of the semiconductorchip (IC) constituting the drain driver 130 becomes much like a squarerather than an elongated plate shape.

Accordingly, with this embodiment, it is possible to increase the numberof chips obtainable from a single wafer as compared to traditionalelongate plate-shaped ones while at the same time making it possible toemploy low-price apparatus when forming semiconductor chips (ICs) on asingle semiconductor wafer by the so-called step-and-repeat exposuretechniques; thus, it is possible to reduce production costs of suchsemiconductor chips (ICs).

It must be noted that in this embodiment, geometrical positioning orlayout of output terminals (BUMP1) is determinable by the size ofsemiconductor chip (IC) and the output terminal number plus distancebetween output terminals; in case the semiconductor chip (IC) is largein size, a minimal area of such semiconductor chip (IC) is attainable bydisposing it in an output terminal region (a) 20 in FIG. 13, which isnearest to the buffer circuit 158.

In case the semiconductor chip (IC) is small in size, it may be designedto use an output terminal region (b) 21.

Additionally with this embodiment, since the output terminals (BUMP1)are disposed at part in close proximity to the center of thesemiconductor chip (IC), in case the semiconductor chip (IC) is mountedon a film substrate by chip-on-film techniques, more than one wiringlayer (COFA) on or over the film substrate for connection between theoutput terminals (BUMP1) of semiconductor chip (IC) and the drain lines(D) of the liquid crystal display panel 10 will partly overlap thesemiconductor chip (IC).

Due to this, with this embodiment, letting the wiring layer (COFA)overlying the film substrate have a layout such as shown in FIG. 14makes it possible to electrically connect together the output terminals(BUMP1) of semiconductor chip (IC) and the drain lines (D) of the liquidcrystal display panel 10 without causing the wiring layer (COFA)overlying film substrate 310 and the output terminals (BUMP1) ofsemiconductor chip (IC) to be brought into contact with each other asshown in FIG. 13.

Additionally, although it has been well known in the semiconductormemory device art to provide the terminal region at the center portionof a semiconductor chip, the reason for provision of the terminal regionat the center in such semiconductor memories is in order to reduceon-chip lead delays, and is not for semiconductor ship cost reduction asin the invention as disclosed and claimed herein.

Embodiment 2

FIG. 15 is a diagram showing a layout of internal circuitry of asemiconductor chip (IC) constituting a drain driver 130 of Embodiment 2of the invention.

This embodiment is the one which is arranged so that a respective one ofthe output circuit blocks which are disposed and stacked into two stagesin the way as has been explained in the above-noted Embodiment 1 isseparated into an output circuit block for outputting a gradation/tonevoltage of the positive polarity and an output circuit block forgenerating a negative-polarity gradation/tone voltage.

More specifically it is separated into an output circuit block(corresponding to an upper-side output circuit block in FIG. 16, whichis represented as “HV” herein) in which the decoder circuit 157 is thehigh-voltage decoder circuit 251 whereas the amplifier circuit 264consists essentially of the high-voltage amplifier circuit 271 and anoutput circuit block (corresponding to a lower-side output circuit blockin FIG. 16, which is represented as “LV” herein) in which the decodercircuit 157 is low-voltage decoder circuit 252 whereas the amp circuit264 consists essentially of the low-voltage amplifier circuit 272.

Additionally the shift register 153 is rendered operative upon receiptof a shift clock as generated at the shift clock generator circuit 254within clock control circuitry, wherein the shift direction of suchshift register circuit 153 is indicated by dot-line arrow in FIG. 15.

In FIG. 15, numerals added to decoder circuit part correspond to outputterminals (BUMP1): The FIG. 15's numerals are interchangeable inaccordance with the level (H level or L level) of a polarity inversionsignal (M) in such a way that No. 1 is changed to No. 2 and No. 2 is toNo. 1, for example.

Due to this, with this embodiment, the shift register circuit 153 isrequired to output a data accept signal per every set of three outputterminals (BUMP1).

Additionally, according to the above-stated embodiment, the shiftregister circuit 153 is designed to output the data accept signal perevery set of six output terminals (BUMP1).

In this embodiment, it is possible to achieve circuit area shrink at thedecoder circuit 157 that has a specified number of voltage bus lineswhich number is given by 64 gray-scale levels x 2=128 lines and the datalatch circuit unit 262 having a predetermined number of display databuses which number is given as 6 bits×6=36 lines.

FIG. 16 is a pictorial diagram showing the structure of a known decodercircuit 157 within a semiconductor chip (IC).

As shown in FIG. 16, conventionally the decoder circuit 157 is such thatswitching elements are disposed beneath a selected number, 128 in total,of aluminum wiring leads (referred to as “AL leads” hereinafter) 150 ofvoltage bus lines of 64 gradation levels or “gray-scales” on the lowvoltage side and voltage bus lines of 64 gray scales on the high voltageside.

Here, looking at the high voltage side (indicated by “High” in FIG. 16)by way of example, to-be-used ones of such 128 voltage bus lines areonly 64 lines corresponding to 64 gray-scale levels on the high voltageside; thus, a space for use with the remaining 64 low-voltage-side linesis a dead region under an assumption that the size of switching elementdoes not serve as any limitation.

The same goes with the low voltage side; hence, let an area at this timebe (a×b).

FIG. 17 is a pictorial diagram showing a structure of the decodercircuit 157 within a semiconductor chip (IC) in accordance with thisembodiment.

As shown in FIG. 17, switch elements of the high-voltage decoder 251 aredisposed beneath wiring leads of 64 gray-scale levels on the highvoltage side whereas switch elements of the low-voltage decoder 252 arelaid out under wiring leads of 64 gray-scale levels on the low voltageside.

Due to this, with this embodiment, any dead region is no longer presentunlike the related art decoder circuit 157 shown in FIG. 17.

Note here that at presently available manufacturing processes, the ALleads 150 are controlling the area in most cases so that it issufficiently possible to dispose switch elements beneath the Al leads150.

The area at this time is given as (a×b)/2, which becomes half (½) of thetraditional decoder circuit 157 shown in FIG. 17.

In this way, with this embodiment, it is possible to reduce by half theresultant circuit area irrespective of the equality of functionality.

Even in the data latch circuit 262 also, for the identically samereason, it is possible to half-reduce the circuit area; thus, it ispossible to significantly reduce an overall area of the drain drivercircuitry.

Embodiment 3

FIG. 18 is a diagram showing a layout of internal circuitry of asemiconductor chip (IC) constituting a drain driver 130 of Embodiment 3of the invention.

This embodiment shown herein is the one which is arranged so that theoutput circuit blocks as have been explained in Embodiment 1 aredisposed and stacked over each other into four stages.

Even with this embodiment, it is possible by disposing the outputterminals (BUMP1) of the same shape in adjacent regions to reduce deadspaces to thereby reduce the area of an output terminal region 20.

Note that although in this embodiment, the area might increase by adegree corresponding to the decoder circuit 157 and data latch unit 262when compared to the case of the two-stage arrangement of Embodiment 1stated supra, it is possible to further reduce the length in thelongitudinal direction (lateral direction).

Thus, it is possible to attain accommodation within an exposureregion(s) when forming semiconductor chips (ICs) on a wafer bystep-and-repeat exposure techniques with an increase in the number ofoutput terminals.

In addition, with tis embodiment, as output terminals (BUMP1) aredisposed into two stages at part adjacent to a central portion of thesemiconductor chip (IC), a wiring layer (COFA) overlying a filmsubstrate for connection between the output terminals (BUMP1) ofsemiconductor chip (IC) and drain lines (D) of liquid crystal displaypanel 10 partly overlaps the semiconductor chip (IC) in case where thesemiconductor chip (IC) is mounted on the film substrate by chip-on-filmtechniques.

Due to this, with this embodiment, it is possible by letting the wiringlayer (COFA) overlying the film substrate have a layout shown in FIG. 19to electrically connect the output terminals (BUMP1) of semiconductorchip (IC) and the drain lines (D) of liquid crystal display panel 10without causing the wiring layer (COFA) of film substrate 310 to comeinto contact with the terminals (BUMP1) of semiconductor chip (IC) asshown in FIG. 18.

Embodiment 4

FIG. 20 is a diagram for explanation of disposal of output terminals(BUMP1) of a semiconductor chip (IC) making up a drain driver 130 ofEmbodiment 4 of the invention.

As shown in FIG. 20, with this embodiment, output terminals (BUMP1) areformed into two separate arrays or “columns,” wherein these outputterminals (BUMP1) are electrically connected to drain lines (D) ofliquid crystal display panel 10 by a wiring layer (COFA) with multipleleads as formed on or over a film substrate 310.

In this case, if the output terminals (BUMP1) are formed into aplurality of columns then the distance or lead pitch is narrowed of thewiring layer (COFA) formed on the film substrate 310 which leads to alikewise decrease in distance between the wiring layer (COFA) of filmsubstrate 310 and its neighboring output terminals (BUMP1), resulting inoccurrence of a disadvantage that the possibility of creation ofelectrical shorting defects gets higher.

Then, with this embodiment, such risks of shorting defect creation maybe avoided by specifically designing the terminals (BUMP1) so that thoseadjacent to the lead take-out direction of the wiring layer (COFA) offilm substrate 310 (i.e. the second column of terminals (BUMP1) withrespect to the first column of terminals (BUMP1) in FIG. 20) areshortened in length in column direction of the output terminals (BUMP1)to thereby lengthen the distance (La of FIG. 20) between the wiringlayer (COFA) of film substrate 310 and its neighboring output terminals(BUMP1).

In addition, in case probe test/inspection is carried out, problems canoccur due to deviation of a probe and an output terminal (BUMP1) as thedistance (pitch) of output terminals (BUMP1) becomes smaller.

Then, with this embodiment, in case probing is done for the outputterminals (BUMP1) as disposed into n (N>1) stages at specified intervalseach corresponding to n pins, let those output terminals (BUMP1) (firstcolumn of output terminals (BUMP1) in FIG. 15) that are disposed farfrom the takeout direction of the wiring layer (COFA) formed on the filmsubstrate 310 increase in length in column direction thereof and thenperform probe test/inspection at this column, thereby avoiding problemsoccurring due to deviation of the probe and output terminal (BUMP1)during the probe test procedure.

In this way, with this embodiment, letting those output terminals(BUMP1) (first column of output terminals (BUMP1) in FIG. 20) adjacentto the takeout direction of the wiring layer (COFA) as formed on thefilm substrate 310 decrease in length in the column direction makes itpossible to preclude electrical shorting defects between the outputterminals (BUMP1) and the wiring layer (COFA) formed on the filmsubstrate 310 and further makes it possible to avoid upon-connectiondefects due to deviation between the probe and output terminal (BUMP1)during probe testing.

Embodiment 5

FIG. 21 is a diagram for explanation of part of terminals (BUMP) of asemiconductor chip (IC) making up a drain driver 130 of Embodiment 5 ofthe invention along with part of a wiring layer (COFB) with multipleleads as formed on a film substrate 310.

The wiring layer (COFB) shown in FIG. 21 is the one that connectstogether the terminals (BUMP) of the semiconductor chip (IC) as mountedon the film substrate 310.

As higher precision and higher performance plus further increases inscreen sizes of liquid crystal display devices are advanced, the draindriver 130 is required to offer higher performances; if this is thecase, an output delay due to influence of load impedances will becomeproblematic in power supply wiring layer(s) and clock wiring layer(s) orelse within the semiconductor chip (IC) that makes up the drain driver130.

Then, as in this embodiment, reinforcing or replacing metal wiring leadsof the semiconductor chip (IC) by the wiring layer (COFB) of filmsubstrate 310 which is low in impedance makes it possible to improve thedriving ability of the drain driver 130.

In addition, as shown in FIG. 22, it will also be possible to connecttogether a plurality of terminals (BUMP) by the same lead and furtherconnect this wiring layer (COFB) to an input terminal(s) of a wiringlayer being formed at outer periphery of the film substrate 310.

Alternatively, as shown in FIG. 23, those terminals (BUMP) that are notable to be put at the outer periphery of the semiconductor chip (IC) areprovided on the inside thereof while connecting the wiring layer (COFB)of film substrate 310 to the internally provided terminals (BUMP) beingprovided on the inside, thereby enabling supplement of a voltage(s) tothe internally provided terminals (BUMP).

It should be noted that although in each embodiment, a specificembodiment has been stated in which the invention is applied to theliquid crystal display panel of the longitudinal electric field mode,the invention should not be limited to this and may also be applicableto liquid crystal display panels of the lateral electric field mode.

Also note that although in each embodiment, a specific one with the dotinversion scheme being applied as the driving method thereof has beenexplained, the invention should not be limited to this and may also beapplicable to common inversion methods for inverting drive voltages asapplied to the pixel electrode (ITO1) and common electrode (ITO2) inunits of lines or alternatively in units of frames.

Further, the invention is also applicable to simple-matrix liquidcrystal display devices.

Although the invention made by the inventor(s) as named herein has beenexplained in detail based on the preferred embodiments, the inventionshould not be limited only to the embodiments and, obviously, may bemodified and altered into a variety of forms without departing from thetrue spirit and scope of the invention.

Effects and advantages obtainable by a representative one of theinventive concepts as disclosed herein will be explained in brief below.

(1) In accordance with the invention, it is possible to reduce costs ofthe liquid crystal display device.

(2) According to the invention, it is possible to simplify the liquidcrystal display device test/inspection procedure.

(3) According to the invention, it is possible to prevent any unwantedvoltage dropdown otherwise occurring due to wiring layers on the insideof a semiconductor integrated circuit device(s).

1. A liquid crystal display device comprising: a plurality of pixels; aplurality of image signal lines for applying a plurality of gray scalevoltages to the plurality of pixels; an image signal line drive unitcomprising a film substrate and a semiconductor integrated circuitdevice formed on the film substrate; wherein the semiconductorintegrated circuit comprises a plurality of input terminals, a pluralityof output terminals, a first terminal, and a second terminal; whereinthe film substrate comprises a plurality of first wirings electricallyconnected to the plurality of image signal lines and the plurality ofoutput terminals of the semiconductor integrated circuit device, aplurality of second wirings electrically connected to the plurality ofinput terminals of the semiconductor integrated circuit, and a thirdwiring electrically connected to the first terminal and the secondterminal of the semiconductor integrated circuit device; and wherein thethird wiring and the first terminal are connected between thesemiconductor integrated circuit device and the film substrate, and thethird wiring and the second terminal are connected between thesemiconductor integrated circuit device and the film substrate.
 2. Aliquid crystal display device according to claim 1, wherein theplurality of first wirings and the plurality of output terminals areconnected between the semiconductor integrated circuit device and thefilm substrate, and the plurality of second wirings and the plurality ofinput terminals are connected between the semiconductor integratedcircuit and the film substrate.
 3. A liquid crystal display deviceaccording to claim 2, wherein the third wiring is formed between thesemiconductor integrated circuit device and the film substrate.
 4. Aliquid crystal display device according to claim 3, wherein a powervoltage of the semiconductor integrated circuit device is applied to thethird wiring.
 5. A liquid crystal display device according to claim 3,wherein a clock signal of the semiconductor integrated circuit device isapplied to the third wiring.
 6. A liquid crystal display deviceaccording to claim 3, wherein the semiconductor integrated circuitdevice comprising a longer edge and a shorter edge, and the third wiringextends in parallel with the longer edge.
 7. A liquid crystal displaydevice according to claim 3, wherein the third wiring is electricallyconnected to an external device of the image signal line drive unit.